RHEL5 incorrect netstat statistics
Folks,
I am running multicast benchmark on RHEL5 systems. One RHEL5 system sends multicast packets and other RHEL5 system is the receiver. I use "netstat -su" to look at the counters and I noticed that whenever I have packet loss the "packet receive errors" is always increased by factor of two (i.e., if 100 packets are lost the counter is increased by 200). Is this a bug or does it increase once for multicast and once to udp? Thanks. |
I would check to see what type of packets you are seeing on the wire with either tcpdump or wireshark.
Also which error count are you looking at? This the output of a machine at work. [me@myhost]$ netstat -su IcmpMsg: InType0: 2325 InType3: 91 InType8: 17 OutType0: 17 OutType3: 248 OutType8: 8752 OutType13: 1 Udp: 4656889 packets received 235 packets to unknown port received. 12 packet receive errors 3527864 packets sent IpExt: InMcastPkts: 200639 OutMcastPkts: 36 InBcastPkts: 5688689 Also which kernel are you running from RHEL5? |
I am looking at "packet receive errors". This is a benchmark environment to nothing much is going on. I can run "netstat -su" all day long and the receive errors counter does not increase. When I run my multicast program and when there is a packet loss this counter is always increased by twice the number of packets lost.
I am running RHEL 5.4 (Tikanga), 2.6.18-164.20.1.el5 kernel. |
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